The dark streaks running down a shingle roof are airborne algae, not soot or mildew — scrubbing or a direct pressure blast won't remove it for good, but a low-pressure soft wash kills the growth instead of just knocking it loose. Left alone, it spreads down the slope and shortens the roof's remaining service life.
A roof doesn't turn black overnight. The streaks start as a faint gray haze near the ridge or in a shaded valley and darken over months as an airborne algae spreads down the slope, feeding on the roofing material itself. By the time it's visible from the curb, it's established enough that a rinse alone won't touch it — the algae has to be killed at the surface, which is the entire reason this is a soft-wash job and not a pressure job.
This is the shingle-roof version of that work. A tile roof gets its own lower-pressure handling for the tile itself, covered separately, since tile and shingle fail in different ways under the wrong pressure. On shingles the risk isn't cracking, it's stripping the protective granules off the surface, which ages that section of roof faster than the algae would have on its own.
What actually goes wrong if you pressure wash a shingle roof instead?
A pressure washer strips the protective granules right along with the algae, and once those granules are gone, that section of the roof weathers faster than the rest for the remainder of its life. A soft wash leaves the granule layer alone and lets the cleaning solution do the work the pressure would otherwise be doing badly.
Fort Lauderdale Pressure Washing's 33 Google reviews average a perfect 5.0, built largely on customers noticing the difference the following year, not just the day of the wash.
How can you tell it's algae and not just a dirty roof?
Algae streaks run in a pattern — down from the ridge, heavier on the side of the roof that gets less direct sun and stays damp longer — and they don't lighten with rain the way surface dirt does. A roof that's evenly dingy all over is usually just dirty; one with dark streaking running in a consistent direction is algae.
Will a soft wash actually kill the algae, or just make it look better for a while?
It kills it — the solution is formulated to work into the algae rather than just rinse the surface, which is the difference between this lasting and the streaks returning within a season. A pressure rinse alone only removes what's already loose, so the roots stay and regrow.
Is this the same service as tile roof cleaning?
No — this is the shingle-roof soft wash. Tile roofs get a separate, even lower-pressure process, since the concern with tile isn't stripping granules, it's cracking the tile or walking on it wrong, which needs different handling entirely.
How urgent is this — can it wait another year?
If there's a visible streaking pattern running down from the ridge or gathering in a shaded valley, it's already established enough to treat. Waiting doesn't pause it — the algae keeps spreading down the slope, and the earlier it's treated, the less of the roof has algae actively feeding on it.
How far out from Fort Lauderdale do you travel for roof work?
Fort Lauderdale Pressure Washing, headquartered at 5390 N State Rd 7, extends roof service to 20 outlying service areas, so coverage reaches well beyond the immediate city.